Key points are not available for this paper at this time.
was present in spatially and temporally variable mixtures, mostly as Fe(III) oxides and phyllosilicates, but with significant fractions of metallic iron (Fe(0)), Fe(II,III) oxide, and Fe(III) bonded to organic carbon. Fe(0) was present as aggregated, nm-sized particles that comprised up to ∼30% of the Fe spectral fraction. Mixtures reflect anthropogenic and geogenic particles subjected to environmental weathering, but reduced Fe in PM originates from anthropogenic sources, likely as abrasion products. Possible mechanistic pathways involving Fe(0) particles and mixtures of Fe(II) and Fe(III) surface species may generate hydrogen peroxide and oxygen-centered radical species (hydroxyl, hydroperoxyl, or superoxide) in Fenton-type reactions. From a health perspective, PM mixtures with reduced and oxidized Fe will have a disproportionate effect in cellular response after inhalation because of their tendency to shuttle electrons and produce oxidants and electrophiles that induce inflammation and oxidative stress.
O’Day et al. (Wed,) studied this question.